1. Field of the Invention
The invention of the present application relates generally to the field of baffles and screens. More particularly, this invention relates to a device for deflecting and dissapating the force of the escaping air which is created during the normal operation of a floor buffing machine having a rotary polishing pad.
2. Description of Related Technology
Electrically operated floor polishers are well known in the art and have been used for some time for polishing and buffing floors. Such machines are used particularly for commercial applications. A machine which is representative of this type is disclosed in the Applicant's U.S. Pat. No. 4,365,377. Typically, such machines include an operator's handle extending upwardly and rearwardly from a pair of mounting wheels attached to the body of the machine. Housed within the machine is a buffing pad mounting for circular rotation about a generally vertically extending, centrally disposed axis extending forwardly from the mounting wheels.
Ideally, the buffing pad rotates at many hundreds of revolutions per minute, the higher speeds resulting in extended life of the floor finish. The result of the high rotational speed of the buffing pad is a correspondingly great velocity for any point on the pad's perimeter. For example, a pad with a diameter of two feet, rotating at 1,500 revolutions per minute, will create a circumferential velocity of about 75 feet per second. An inherent result of such high speed rotation is the creation of air turbulence, which can result in the dislodging and distribution of particulate material from the floor during the floor polishing operation.
In many prior art floor polising machines, the problem of air turbulence was somewhat attenuated because of both lower buffing pad rotation speeds and the tendency of earlier machines to permit non-uniform pad surface contact with the surface of the floor. However, current floor polishing machines such as the one disclosed in U.S. Pat. No. 4,365,377, combine high rotational speed of the pad with an improved pad retaining structure, thereby resulting in uniform pad contact over the pad's entire surface area. During the buffing operation, a small volume of air is continuously being displaced from beneath the pad through the very small cross sectional area between the pad surface and the floor. Particles coming into contact with the polishing pad can therefore exit from beneath the machine's housing at speeds of 100 miles per hour, creating a potential safety hazard.
In order to protect the area adjacent to the polishing machine from the air turbulence created by the machine's operation, prior art devices have sought to place an impermeable shield around the bottom lip of the machine's housing. To prevent scratching the surface of the floor, the shield was required to have a small clearance from the floor. Although such shields are effective in blocking the escape of some of the particulate material disturbed by the buffing operation, the exit velocities from beneath the shield are still unacceptably large because the entire volume of disturbed air is being forced to exit the machine's housing through the relatively small cross sectional area beneath the shield. Any effort to reduce velocities by increasing the clearance of the shield necessarily reduces its effectiveness in blocking the escape of particulate matter.